〈 Berger | Dillon 〉

Question: I always read that baryogenesis is why we have matter but not antimatter in our universe, we just don't understand why it happened. But how do we know *that* it happened?

If matter and antimatter were created in equal amounts, then they'd all have annihilated and we'd be left with nothing but a photon Universe! The very fact that we exist tells us that there had to be more of one type of stuff than the other.

Thank you for taking the time to explain! You say there *had* to be more matter than antimatter to begin with. But that's only true if both matter and antimatter are equally stable, right? So how do we know *that* has to be true?

As we understand it, antimatter is exactly like matter, just opposite charge. So there had to be more matter for there to be matter left over. Of course, figuring out why this happened is part of why physics exists! Which means looking into differences b/w them + other things.

So it's possible that there are other differences between matter and antimatter (other than charge) that account for why there is more of one than the other, but we simply haven't discovered them yet?

We have no idea. That's why we do this.

It’s possible that there could exist other quantum numbers (charge, color, etc) that are conserved at a higher energy scales.. but given the success of the standard model at ~10TeV it is unlikely that antimatter possesses additional properties

I really wish I understood all this stuff better. I have a high level understanding of what you folks do, but its hard to find any resources that go in more detail that dont require a degree in physics :-D